We intend to investigate the genomic organization of hemoglobin, histone, and ribosomal genes in a number of primates. This investigation will involve solution reassociation analyses, construction of restriction endonuclease maps and detailed structural organization by electronmicroscopy. Through these studies we hope to reveal non-transcribed DNA sequences which affect the expression of transcribed gene sequences. A second line of inquiry involves analysis of the DNA sequence organization of individual human chromosomes. We will examine a series of mouse x human somatic hybrid cell lines, in which the human chromosomal complement has been reduced to a single autosome, to determine if individual autosomes are distinguished by unique complements of reiterated sequences. Those cell lines containing human autosomes with unique sets of reiterated sequences will be subjected to further analysis involving "isolation by exclusion" and digestion with restriction endonucleases. Detailed analyses of the organization of human X and Y chromosomes will be extended by restriction endonuclease analyses. Our particular interest will be to isolate DNA sequences from the short arms of these chromosomes.